Problem 18 - Biology the Easy Way (E-Z Biology)

Question

In a chemical formula, each element is represented by its (a) atomic number (c) atomic mass (b) chemical symbol (d) electric charge

Step-by-Step Solution

Answer

Elements are represented by their chemical symbol.

Step 1: Understanding the Question

In this exercise, we need to identify how elements are represented in a chemical formula. Chemical formulas use specific notations to indicate elements and their quantities.

Step 2: Define Key Concepts

Let's define each term: - Atomic number: The number of protons in an atom's nucleus, unique to each element. - Atomic mass: The mass of an atom usually in atomic mass units (amu). - Chemical symbol: A one or two-letter abbreviation derived from the element's English or Latin name. - Electric charge: The charge on an ion, indicating a loss or gain of electrons.

Step 3: Elimination Process

Go through the options for how elements are represented: - Atomic number and atomic mass are not directly shown in a formula. - Electric charge is used for ions but not for element representation. The chemical symbol is used as the shorthand representation in formulas.

Step 4: Conclusion

Based on the definitions and elimination process, the correct representation of elements in a chemical formula is through their chemical symbol (Option b).

Key Concepts

Chemical Symbol

A chemical symbol is like a unique username for each element on the periodic table. It's a shorthand way of representing an element using one or two letters. These letters often come from the element's name in English or Latin. For example:

• "H" stands for Hydrogen
• "O" stands for Oxygen
• "Ag" comes from "argentum," which is Latin for silver

Having a concise chemical symbol makes it easy to write chemical reactions and formulas. Instead of writing out full element names, chemists use these symbols, making everything more manageable and universal across different languages and regions. This simplifies communication and avoids confusion in scientific discussions.

Atomic Number

The atomic number is a fundamental property of an element. It is the total count of protons located in the nucleus of an atom. Protons carry a positive charge, and they help to define the identity of an element. Each element on the periodic table has a unique atomic number. For instance:

• Hydrogen has an atomic number of 1
• Carbon has an atomic number of 6
• Iron has an atomic number of 26

The atomic number not only identifies an element but also dictates its position on the periodic table. As you move from one element to the next, the atomic number increases by one. This property is crucial when predicting how an element behaves in chemical reactions. Knowing the atomic number can also help determine the electron configuration of an element, giving insight into its chemical properties.

Atomic Mass

Atomic mass, often measured in atomic mass units (amu), represents the average mass of an element's atoms, accounting for the different isotopes and their relative abundance. The atomic mass is typically found below the element symbol on the periodic table. Here are some examples:

• Hydrogen has an average atomic mass of approximately 1.008 amu
• Oxygen has an average atomic mass of about 16.00 amu
• Iron, on average, has an atomic mass of roughly 55.85 amu

While the atomic number is always an integer, the atomic mass might not be, due to the presence of isotopes. Isotopes are varieties of an element that have the same number of protons but different numbers of neutrons, which affects the atomic mass. Understanding atomic mass is important for calculations in chemistry, such as determining the amount of substance involved in a reaction.

Electric Charge

Electric charge refers to the presence of charged particles within an atom, indicating a difference in the number of protons versus electrons. Atoms can gain or lose electrons, leading to an imbalance. This results in ions, which have either a positive or negative charge depending on the gain or loss of electrons.There are two main types of ions:

• Cations: Positive ions formed when an atom loses one or more electrons. For example, a sodium atom becomes a sodium ion (\(\text{Na}^+\)).
• Anions: Negative ions created when an atom gains electrons, like chloride forming from chlorine (\(\text{Cl}^-\)).

Electric charge is critical in forming ionic compounds. It's essential to balance charges to maintain neutrality in a compound, like ensuring that the overall charge in sodium chloride (\(\text{NaCl}\)) is zero. Knowing about electric charges helps us understand reactivity, bonding, and the behavior of substances in an electric field.